I'm wondering if your hotter load are trying to open the bolt too soon, leaving the case head somewhat un-supported during cycling operations.

To check this, clean everything up swab the chamber of debris and oil, you do not want oil in the chamber when you fire this. If you think it's safe to shoot, using a pristine case, shoot it again, one more time! But take the bolt apart first, you don't want the extractor or ejector contaminating the results. Measure the case for the bulge Before and After the test. Shoot the weapon single shot , BUT with the mag in the weapon. Single load it manually into the chamber!

Remember to shoot this with an unloaded Magazine in the weapon (important).

Bang!

First, did the BCG hold open? Second you better have a larger type Cleaning Rod with say a 375 Jag and then lightly bang the case out from the chamber. Thirdly, measure and examine the fired case. If no bulge can be observed or measured then a slower powder is in order. But no matter what, this should point out the deficiencies you are looking for. Like, because you used a pristine case, are the scratches gone?

You might have a high probability of being correct, but what I wrote hasn't been discussed. Testing for it will narrow down, some of the unknowns and if my theory turns in a positive, then things like porting come into play, in other words, my little test might disprove some of the theories or point to other solutions??

Like you said, something like, it's difficult to trouble shoot from an electronic arm chair..

..t

PS.. I misspoke (which is why you should never trust anything from the web, including here) it's not opening to fast. I meant to say it might be "Opening to Soon". And Hoot may still be right. Tests will tell..t

Hoot wrote:Looking at that chamber wall thickness, have that bad boy re-chambered into a 450b!

Hoot

Hoot,

I have CERTAINLY considered it! Would be nice to have a single shot to go along with my bolt action. What do you say Wildcatter? Can the extractor be modified to work with the rebated rim??

Yes, but calling the company and find out if the .473" (the 30-06 rim/family of cartridges) extractor would work in that single shot might actually be better of course in any event, IRT that single shot and I hope that's what we are talking about now,

Hoot wrote:Looking at that chamber wall thickness, have that bad boy re-chambered into a 450b!

Hoot

Hoot,

I have CERTAINLY considered it! Would be nice to have a single shot to go along with my bolt action. What do you say Wildcatter? Can the extractor be modified to work with the rebated rim??

Yes, but calling the company and find out if the .473" (the 30-06 rim/family of cartridges) extractor would work in that single shot might actually be better of course in any event, IRT that single shot and I hope that's what we are talking about now,

They do offer the H&R in calibers that use that rim. A 22-250, 243, 25-06, 308, so they do have an extractor for that rim. Now, whether or not they will sell that part...I don't know. Maybe direct to a 'smith, but I haven't called them yet to find out.

It's not the size of the Dog in the Fight that matters....It's the amount of Fight in the Dog!

Your Blackhawk has a cylinder gap that lowers cylinder pressure. Your single shot does not. I used to load for a 357 Colt python. My loads worked fine in the Python but a friend wanted to try in his S&W and it locked it up. So you follow good reloading practices and develop each gun load individually. Then if you want to load one load for both use the lower of the two.